1. Field of the Invention
The present invention relates to a control device operable at the start of power supply to a large scale integrated circuit (LSI), for example of the C-MOS type.
2. Description of the Prior Art
The conventional C-MOS LSI employed in electronic devices such as electronic calculators has a so-called automatic power-down mode in which the power supply is continued to the memory part alone but is automatically discontinued to all other circuits for saving power in case key operations are not conducted for a determined period.
Such a device can be activated by supplying power to such other circuits with a power-on key. Also at the start of power supply by mounting the battery, the operation of the device is automatically initiated by clearing the internal memory of LSI.
Such an LSI has resulted in the following drawbacks in, for example, an electronic device with a printer.
In a usual electronic calculator with a printer, a print such as "CLEAR" is recorded on the recording sheet at the start of power supply in order to indicate such start. Also at battery replacement such an electronic calculator has to be turned upside down because the battery case is positioned at the bottom.
If the electronic calculator is immediately activated at the battery loading, there is initiated the operation of printing "CLEAR" etc., and there may result sheet feeding troubles because the calculator is placed upside down in this state and printing troubles because of undesired key actuations.
Also incomplete contact with the contact leads at battery replacement may cause chattering, thus disabling the normal operation of printing "CLEAR" because the power supply is interrupted and reestablished again before the printing operation is completed.